0.4.0: NBT key fix + hub UI + /bns open + network hardening

Post-review fixes from the parallel code/security/hotkey/NPC audits.

## #35 — NBT keys (CRITICAL: screens were showing fictional data)
ServerEconomyBridge.pushBountySnapshot now reads the actual KubeJS keys:
- bnsBountyPool (compound id->1) — was bnsBounties.pool
- bnsBountyActive (compound id->{progress,target,reward,...}) — was bnsBounties.active
- bnsBountyCompleted (compound id->long cooldown-end-ms) — was bnsBounties.completed
- Filters completed by `cooldown-end > now` so old cooldowns drop off

ServerEconomyBridge.pushPlotSnapshot now reads server-scope state via
KubeJS's MinecraftServer mixin (kjs$getPersistentData) using reflection,
no compileOnly dep on KubeJS. Falls back to empty CompoundTag if the
method isn't there. Resolves owner names from PlayerList for online
players, GameProfileCache for offline.

## #36 — Hub UI + key rebind
Single primary key: B opens HubScreen. Direct shortcut keys (K/J/N/H/M)
all default to UNBOUND so they no longer compete with the ~100 other
pack mods. Audit found M = vanilla Social Interactions + FTB Chunks
fullscreen map (hard conflict, removed); H/N collided with Voice Chat
toggles (minor, removed); K/J were safe (kept rebindable for power users).

New HubScreen routes to the 5 sub-screens via labelled buttons + shows
tier/balance/fee at a glance in the header.

## #37 — /bns open <screen>
Java-registered Brigadier subcommand at RegisterCommandsEvent time,
merges with KubeJS's /bns root. New OpenScreenPacket (S2C) pushes a
screen open to the calling player. Screens: hub, tier, bounty, plot,
shop, questlog. Suggests valid screens via tab-complete.

This unlocks:
- Easy NPC dialogue COMMAND actions calling /bns open shop, etc.
- FTB Quests reward commands
- Command blocks / /trigger objectives
- Future scripted intros / tutorials

Also: patched /srv/fast/brass-sigil-server/server/config/easy_npc/
security.cfg to allow `bns` in executeAsUserCommandAllowList.ALL.

## #38 — Network hardening
- Per-player token bucket on C2S packets (10/s sustain, 20 burst).
- All STRING_UTF8 codecs capped: kind=8, args=80, which=16.
- Verb whitelist replaced with structured parse: args -> tokens ->
  per-verb regex validators -> rebuilt command. No more prefix-match
  surprises if /bns sell syntax expands.
- Per-player in-flight guard on tier upgrades (500ms) closes the
  double-spend race window.
- Bridge logs sanitised (control-char-stripped) so a hostile client
  can't inject newlines/ANSI into server logs.

## Review-driven nits also folded in
- Per-player tickCount (was shared static — N-player skew)
- VillagerTradeRebalance: try/catch around inner.getOffer; null cost-A
  passthrough; round-to-nearest denom split (was floor, ~10% price haircut)
- SpurHud caches Component refs (avoid 120/s allocation)
- ClientBnsState.completedIds now HashSet (O(1) per-frame lookups)
- BountyBoardScreen: deleted the empty `if (isActive)` dead branch
- Wire-format version bumped 0.2 -> 0.4 (added OpenScreenPacket)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

gradle.properties

@@ -19,5 +19,5 @@ loader_version_range=[1,)
 mod_id=bnstoolkit
 mod_name=Brass and Sigil Toolkit
 mod_license=All Rights Reserved
-mod_version=0.3.1
+mod_version=0.4.0
 mod_group_id=uk.sijbers.bnstoolkit

src/main/java/uk/sijbers/bnstoolkit/BnsToolkit.java

@@ -53,17 +53,13 @@ public final class BnsToolkit {
         }
     }
 
-    private static int tickCounter = 0;
-
     @SubscribeEvent
     public void onPlayerTick(PlayerTickEvent.Post event) {
         // 1 Hz balance push so the HUD reflects coin-pickup without polling
-        // the inventory client-side.
+        // the inventory client-side. Per-player tick counter (not a shared
-        if (event.getEntity() instanceof ServerPlayer sp) {
+        // static) so the push rate is 1Hz/player and naturally staggered.
-            tickCounter++;
+        if (event.getEntity() instanceof ServerPlayer sp && sp.tickCount % 20 == 0) {
-            if (tickCounter % 20 == 0) {
             ServerEconomyBridge.pushTierUpdate(sp);
         }
     }
-    }
 }

src/main/java/uk/sijbers/bnstoolkit/client/BnsKeyBindings.java

@@ -10,6 +10,7 @@ import net.neoforged.neoforge.client.settings.KeyConflictContext;
 import org.lwjgl.glfw.GLFW;
 import uk.sijbers.bnstoolkit.BnsToolkit;
 import uk.sijbers.bnstoolkit.client.screens.BountyBoardScreen;
+import uk.sijbers.bnstoolkit.client.screens.HubScreen;
 import uk.sijbers.bnstoolkit.client.screens.PlotPurchaseScreen;
 import uk.sijbers.bnstoolkit.client.screens.QuestLogScreen;
 import uk.sijbers.bnstoolkit.client.screens.ShopBrowserScreen;
@@ -17,66 +18,88 @@ import uk.sijbers.bnstoolkit.client.screens.TierUpgradeScreen;
 import uk.sijbers.bnstoolkit.network.NetSend;
 
 /**
- * Key bindings for the toolkit screens.
+ * Key bindings for the bnstoolkit screens.
  *
- * Default keys avoid known FTB Quests / Chunks / Inventory defaults:
+ * <p>Single primary key: <b>B</b> opens the hub screen, which has buttons
- *   K  — Civic tier ladder  (replaces vanilla advancements which is L)
+ * routing to each sub-screen. Power users can also bind direct shortcuts
- *   J  — Bounty board
+ * to the 5 sub-screens (defaults are UNBOUND so they don't compete with
- *   N  — Plot map / office
+ * the other ~100 mods in the pack).
- *   M  — Quest log overview
  *
- * Picked so they sit on the home row right-hand side and don't clash
+ * <p>Audit context for choosing B as default (2026-06-07):
- * with WASD movement / vanilla / FTB defaults. Player can rebind in the
+ * <ul>
- * vanilla controls menu like any other mod.
+ *   <li>Vanilla 1.21.1: B is free</li>
+ *   <li>FTB Quests / FTB Chunks / FTB Library: B is free</li>
+ *   <li>Numismatics / Easy NPC / JEI / Patchouli: B is free</li>
+ *   <li>Simple Voice Chat, Curios, Ars Nouveau, Better Combat, Sophisticated
+ *       Backpacks: B is free</li>
+ * </ul>
+ * Sub-screen keys (K/J/N/H/M) had conflicts — most notably M against
+ * vanilla Social Interactions + FTB Chunks fullscreen map — so they're
+ * intentionally UNBOUND now.
  */
 public final class BnsKeyBindings {
     private BnsKeyBindings() {}
 
     private static final String CATEGORY = "key.category." + BnsToolkit.MOD_ID;
 
+    public static final KeyMapping OPEN_HUB = new KeyMapping(
+            "key." + BnsToolkit.MOD_ID + ".hub",
+            KeyConflictContext.IN_GAME,
+            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_B),
+            CATEGORY);
+
+    // Direct shortcuts — default UNBOUND. Players can bind them in the
+    // vanilla controls menu under the "Brass and Sigil" category if they
+    // want speed over discoverability.
     public static final KeyMapping OPEN_TIER = new KeyMapping(
             "key." + BnsToolkit.MOD_ID + ".tier",
             KeyConflictContext.IN_GAME,
-            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_K),
+            InputConstants.UNKNOWN,
             CATEGORY);
 
     public static final KeyMapping OPEN_BOUNTIES = new KeyMapping(
             "key." + BnsToolkit.MOD_ID + ".bounties",
             KeyConflictContext.IN_GAME,
-            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_J),
+            InputConstants.UNKNOWN,
             CATEGORY);
 
     public static final KeyMapping OPEN_PLOTS = new KeyMapping(
             "key." + BnsToolkit.MOD_ID + ".plots",
             KeyConflictContext.IN_GAME,
-            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_N),
+            InputConstants.UNKNOWN,
             CATEGORY);
 
     public static final KeyMapping OPEN_SHOP = new KeyMapping(
             "key." + BnsToolkit.MOD_ID + ".shop",
             KeyConflictContext.IN_GAME,
-            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_H),
+            InputConstants.UNKNOWN,
             CATEGORY);
 
     public static final KeyMapping OPEN_QUESTLOG = new KeyMapping(
             "key." + BnsToolkit.MOD_ID + ".questlog",
             KeyConflictContext.IN_GAME,
-            InputConstants.Type.KEYSYM.getOrCreate(GLFW.GLFW_KEY_M),
+            InputConstants.UNKNOWN,
             CATEGORY);
 
     public static void onRegisterKeyMappings(RegisterKeyMappingsEvent event) {
+        event.register(OPEN_HUB);
         event.register(OPEN_TIER);
         event.register(OPEN_BOUNTIES);
         event.register(OPEN_PLOTS);
         event.register(OPEN_SHOP);
         event.register(OPEN_QUESTLOG);
-        BnsToolkit.LOG.info("[bnstoolkit] registered 5 key bindings under {}", CATEGORY);
+        BnsToolkit.LOG.info("[bnstoolkit] registered key bindings (B = hub; others unbound by default)");
     }
 
     @SubscribeEvent
     public static void onClientTick(ClientTickEvent.Post event) {
         Minecraft mc = Minecraft.getInstance();
         if (mc == null || mc.player == null || mc.screen != null) return;
+        if (OPEN_HUB.consumeClick()) {
+            NetSend.requestSnapshot("ALL");
+            new HubScreen().openGui();
+        }
+        // Direct shortcuts — only fire if the player actually bound a key
         if (OPEN_TIER.consumeClick()) {
             NetSend.requestSnapshot("TIER");
             new TierUpgradeScreen().openGui();

src/main/java/uk/sijbers/bnstoolkit/client/ClientBnsState.java

@@ -6,8 +6,10 @@ import uk.sijbers.bnstoolkit.data.Plot;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Client-side cache of the player's economy state, populated by S2C
@@ -34,7 +36,7 @@ public final class ClientBnsState {
     // BountySnapshot:
     public static final List<String> dailyPoolIds = new ArrayList<>();
     public static final Map<String, ActiveBounty> activeBounties = new HashMap<>();
-    public static final List<String> completedIds = new ArrayList<>();
+    public static final Set<String> completedIds = new HashSet<>();
     public static volatile int bountySlotCap = 3;
 
     // PlotSnapshot:

src/main/java/uk/sijbers/bnstoolkit/client/OpenScreenDispatcher.java

@@ -0,0 +1,34 @@
+package uk.sijbers.bnstoolkit.client;
+
+import uk.sijbers.bnstoolkit.BnsToolkit;
+import uk.sijbers.bnstoolkit.client.screens.BountyBoardScreen;
+import uk.sijbers.bnstoolkit.client.screens.HubScreen;
+import uk.sijbers.bnstoolkit.client.screens.PlotPurchaseScreen;
+import uk.sijbers.bnstoolkit.client.screens.QuestLogScreen;
+import uk.sijbers.bnstoolkit.client.screens.ShopBrowserScreen;
+import uk.sijbers.bnstoolkit.client.screens.TierUpgradeScreen;
+import uk.sijbers.bnstoolkit.network.NetSend;
+
+/**
+ * Maps the string-keyed S2C OpenScreenPacket payload to the
+ * corresponding client-side screen open. Lives in the client package
+ * so the packet class itself doesn't have to import screen classes —
+ * which keeps the dedicated server from trying to load them.
+ */
+public final class OpenScreenDispatcher {
+    private OpenScreenDispatcher() {}
+
+    public static void open(String which) {
+        // Each branch requests the matching snapshot then opens the screen
+        // so the panel renders with data instead of zeros.
+        switch (which) {
+            case "tier"     -> { NetSend.requestSnapshot("TIER");   new TierUpgradeScreen().openGui(); }
+            case "bounty"   -> { NetSend.requestSnapshot("BOUNTY"); new BountyBoardScreen().openGui(); }
+            case "plot"     -> { NetSend.requestSnapshot("PLOT");   new PlotPurchaseScreen().openGui(); }
+            case "shop"     -> { NetSend.requestSnapshot("SELL");   new ShopBrowserScreen().openGui(); }
+            case "questlog" -> { NetSend.requestSnapshot("ALL");    new QuestLogScreen().openGui(); }
+            case "hub"      -> { NetSend.requestSnapshot("ALL");    new HubScreen().openGui(); }
+            default -> BnsToolkit.LOG.warn("[bnstoolkit] unknown screen requested: {}", which);
+        }
+    }
+}

src/main/java/uk/sijbers/bnstoolkit/client/hud/SpurHud.java

@@ -3,7 +3,6 @@ package uk.sijbers.bnstoolkit.client.hud;
 import net.minecraft.client.DeltaTracker;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiGraphics;
-import net.minecraft.client.gui.LayeredDraw;
 import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
 import net.neoforged.neoforge.client.event.RegisterGuiLayersEvent;
@@ -16,10 +15,9 @@ import uk.sijbers.bnstoolkit.data.CivicTier;
 /**
  * Persistent on-screen overlay: civic tier + spurs balance, top-left.
  *
- * Drawn as a NeoForge {@link RegisterGuiLayersEvent} layer rather than a
+ * Registered as a NeoForge gui layer (above the experience bar) so it
- * {@code RenderGuiEvent} subscriber so it composes cleanly with the
+ * composes cleanly with the vanilla HUD chain — F1 hide, chat focus,
- * vanilla layer system (and hides automatically when chat / inventory
+ * and pause screens all suppress us automatically.
- * suppresses HUD).
  */
 public final class SpurHud {
     private SpurHud() {}
@@ -28,6 +26,13 @@ public final class SpurHud {
     public static final ResourceLocation LAYER_ID =
             ResourceLocation.fromNamespaceAndPath(BnsToolkit.MOD_ID, "spur_hud");
 
+    // Cache the rendered Component objects, rebuild only when the state changes.
+    // Keeps allocation off the 60 Hz render path.
+    private int cachedTier = -1;
+    private long cachedSpurs = -1L;
+    private Component cachedTierLine = Component.empty();
+    private Component cachedSpursLine = Component.empty();
+
     public static void onRegisterGuiLayers(RegisterGuiLayersEvent event) {
         event.registerAbove(VanillaGuiLayers.EXPERIENCE_BAR, LAYER_ID, INSTANCE::render);
         BnsToolkit.LOG.info("[bnstoolkit] HUD layer registered as {}", LAYER_ID);
@@ -38,13 +43,18 @@ public final class SpurHud {
         if (mc == null || mc.player == null) return;
         if (mc.options.hideGui) return;
 
+        if (cachedTier != ClientBnsState.tier || cachedSpurs != ClientBnsState.spurs) {
             CivicTier cfg = CivicTier.byId(ClientBnsState.tier);
-        String tierLine = "§" + cfg.colour().getChar() + cfg.name() + "§r";
+            cachedTierLine = Component.literal("§" + cfg.colour().getChar() + cfg.name() + "§r");
-        String spursLine = "§6" + TierUpgradeScreen.formatSpurs(ClientBnsState.spurs) + " spurs§r";
+            cachedSpursLine = Component.literal("§6" + TierUpgradeScreen.formatSpurs(ClientBnsState.spurs) + " spurs§r");
+            cachedTier = ClientBnsState.tier;
+            cachedSpurs = ClientBnsState.spurs;
+        }
 
         int x = 4;
         int y = 4;
-        int w = Math.max(mc.font.width(tierLine), mc.font.width(spursLine)) + 8;
+        int textW = Math.max(mc.font.width(cachedTierLine), mc.font.width(cachedSpursLine));
+        int w = textW + 8;
         int h = 24;
 
         gfx.fill(x, y, x + w, y + h, 0x80000000);
@@ -53,17 +63,7 @@ public final class SpurHud {
         gfx.fill(x, y, x + 1, y + h, 0xFF666666);
         gfx.fill(x + w - 1, y, x + w, y + h, 0xFF666666);
 
-        gfx.drawString(mc.font, Component.literal(tierLine), x + 4, y + 4, 0xFFFFFFFF, true);
+        gfx.drawString(mc.font, cachedTierLine, x + 4, y + 4, 0xFFFFFFFF, true);
-        gfx.drawString(mc.font, Component.literal(spursLine), x + 4, y + 14, 0xFFFFFFFF, true);
+        gfx.drawString(mc.font, cachedSpursLine, x + 4, y + 14, 0xFFFFFFFF, true);
     }
-
-    // Kept for symmetry with the LayeredDraw.Layer interface in case other
-    // code wants to call the render directly.
-    public void renderRaw(GuiGraphics gfx, DeltaTracker delta) {
-        render(gfx, delta);
-    }
-
-    // Reference suppression so unused imports don't warn.
-    @SuppressWarnings("unused")
-    private static final LayeredDraw.Layer UNUSED_REF = null;
 }

src/main/java/uk/sijbers/bnstoolkit/client/screens/BountyBoardScreen.java

@@ -149,7 +149,6 @@ public final class BountyBoardScreen extends BaseBnsScreen {
             if (ab != null) add(new HeaderRow(this, "Progress: " + ab.progress() + " / " + ab.target()));
 
             boolean atCap = ClientBnsState.activeBounties.size() >= ClientBnsState.bountySlotCap;
-            boolean isActive = s == Bounty.State.ACTIVE || s == Bounty.State.READY;
 
             if (s == Bounty.State.AVAILABLE && !atCap) {
                 add(SimpleTextButton.create(this, Component.literal("Accept"), Icons.ACCEPT,
@@ -166,8 +165,6 @@ public final class BountyBoardScreen extends BaseBnsScreen {
             if (s == Bounty.State.AVAILABLE && atCap) {
                 add(new HeaderRow(this, "§cAt bounty slot cap — upgrade your tier or cancel one first."));
             }
-            // ignore isActive flag silently; included for future buttons
-            if (isActive) { /* visual cue handled via row marker */ }
         }
 
         @Override public void alignWidgets() {

src/main/java/uk/sijbers/bnstoolkit/client/screens/HubScreen.java

@@ -0,0 +1,96 @@
+package uk.sijbers.bnstoolkit.client.screens;
+
+import dev.ftb.mods.ftblibrary.icon.Color4I;
+import dev.ftb.mods.ftblibrary.icon.Icon;
+import dev.ftb.mods.ftblibrary.icon.Icons;
+import dev.ftb.mods.ftblibrary.ui.Panel;
+import dev.ftb.mods.ftblibrary.ui.SimpleTextButton;
+import dev.ftb.mods.ftblibrary.ui.Theme;
+import dev.ftb.mods.ftblibrary.ui.Widget;
+import net.minecraft.client.gui.GuiGraphics;
+import net.minecraft.network.chat.Component;
+import uk.sijbers.bnstoolkit.client.ClientBnsState;
+import uk.sijbers.bnstoolkit.data.CivicTier;
+import uk.sijbers.bnstoolkit.network.NetSend;
+
+/**
+ * Brass and Sigil hub — the single entry point opened by the B key.
+ *
+ * Header: current tier (in tier colour) + spurs balance.
+ * Body: 5 large buttons that route to the sub-screens. Clicking a button
+ * fires the matching snapshot request and opens the screen — same flow
+ * as the (now mostly-unbound) direct shortcut keys.
+ *
+ * Closing a sub-screen returns to the hub (so this hub becomes a real
+ * navigation surface, not a one-shot menu).
+ */
+public final class HubScreen extends BaseBnsScreen {
+
+    public HubScreen() {
+        super(Component.translatable("screen.bnstoolkit.hub"));
+    }
+
+    @Override
+    public void addWidgets() {
+        add(new StatusHeader(this));
+
+        add(makeButton("Civic Tier",       Icons.PLAYER,   "TIER",   () -> new TierUpgradeScreen()));
+        add(makeButton("Bazaar Shop",      Icons.ADD,      "SELL",   () -> new ShopBrowserScreen()));
+        add(makeButton("Bounty Board",     Icons.ACCEPT,   "BOUNTY", () -> new BountyBoardScreen()));
+        add(makeButton("Plot Office",      Icons.FRIENDS,  "PLOT",   () -> new PlotPurchaseScreen()));
+        add(makeButton("Quest Log",        Icons.INFO,     "ALL",    () -> new QuestLogScreen()));
+        add(SimpleTextButton.create(this, Component.literal("Close"), Icons.CLOSE,
+                btn -> closeGui()));
+    }
+
+    @Override
+    public void alignWidgets() {
+        // Header across the top
+        Widget header = getWidgets().get(0);
+        header.setPos(getX() + 8, contentTop());
+        header.setSize(getWidth() - 16, 20);
+
+        // 5 routing buttons stacked vertically in two columns
+        int cols = 2;
+        int btnW = (getWidth() - 24) / cols;
+        int btnH = 22;
+        int gap = 4;
+        int top = contentTop() + 28;
+        for (int i = 0; i < 5; i++) {
+            int row = i / cols;
+            int col = i % cols;
+            Widget w = getWidgets().get(1 + i);
+            w.setSize(btnW, btnH);
+            w.setPos(getX() + 8 + col * (btnW + gap), top + row * (btnH + gap));
+        }
+
+        // Close button bottom-right
+        Widget close = getWidgets().get(6);
+        close.setSize(64, 16);
+        close.setPos(getX() + getWidth() - 72, getY() + getHeight() - 22);
+    }
+
+    private SimpleTextButton makeButton(String label, Icon icon, String snapshot,
+                                         java.util.function.Supplier<BaseBnsScreen> ctor) {
+        return SimpleTextButton.create(this, Component.literal(label), icon, btn -> {
+            NetSend.requestSnapshot(snapshot);
+            ctor.get().openGui();
+        });
+    }
+
+    /** Status header — tier, balance, fee at the top of the hub. */
+    private static final class StatusHeader extends Widget {
+        StatusHeader(Panel parent) { super(parent); }
+        @Override public void draw(GuiGraphics gfx, Theme theme, int x, int y, int w, int h) {
+            Color4I.rgba(0x40FFFFFF).draw(gfx, x, y, w, h);
+            CivicTier cfg = CivicTier.byId(ClientBnsState.tier);
+            String left = "Tier: §" + cfg.colour().getChar() + cfg.name() + "§r";
+            String right = "Balance: §6" + TierUpgradeScreen.formatSpurs(ClientBnsState.spurs)
+                    + "§r  §7(fee " + ClientBnsState.effectiveFeePct + "%)§r";
+            theme.drawString(gfx, Component.literal(left), x + 4, y + 6, Color4I.WHITE, Theme.SHADOW);
+            int rightW = theme.getFont().width(right);
+            theme.drawString(gfx, Component.literal(right), x + w - rightW - 4, y + 6,
+                    Color4I.WHITE, Theme.SHADOW);
+        }
+    }
+}

src/main/java/uk/sijbers/bnstoolkit/economy/VillagerTradeRebalance.java

@@ -22,25 +22,30 @@ import java.util.Optional;
 /**
  * Server-side villager-trade rebalance.
  *
- * Hooks {@link VillagerTradesEvent} and {@link WandererTradesEvent} at
+ * Wraps every trade listing on {@link VillagerTradesEvent} (and the
- * data-pack-reload time. For every existing trade listing, swaps any
+ * wanderer trades) so the resulting {@link MerchantOffer} has its
- * emerald cost/result for the Numismatics equivalent (1 spur = 1
+ * emerald cost-or-result items swapped to Numismatics coin equivalents.
- * emerald), so the entire vanilla and modded villager trade table
- * routes through the BNS economy without us having to enumerate every
- * profession + level by hand.
  *
- * Counts >= 8 are upgraded to higher denominations so inventory doesn't
+ * <h2>Denomination choice</h2>
- * fill up with raw spurs:
+ * For each emerald count we pick a single denomination that minimises
- *   1..7   spurs     (1 each)
+ * the rounding error:
- *   8..63  -> bevels (1 bevel  = 8 spurs)
+ * <ul>
- *   64..   -> cogs   (1 cog    = 64 spurs)
+ *   <li>1..7 emeralds → spurs (1 spur = 1 emerald)</li>
+ *   <li>8..63 emeralds → bevels, rounding to nearest (1 bevel = 8 spurs)</li>
+ *   <li>64+ emeralds → cogs, rounding to nearest (1 cog = 64 spurs)</li>
+ * </ul>
+ * Round-to-nearest avoids the 10–12% silent price haircut from floor-division.
+ * MerchantOffer constraints require a single ItemCost per slot (no
+ * multi-denom split possible at this layer).
  *
- * Why this lives in bnstoolkit rather than a third-party mod:
+ * <h2>Robustness</h2>
- *   - The two existing options on Modrinth (numismatics-villager-currency
+ * <ul>
- *     and data-trades) either require a NeoForge bump (1.1.0 wants
+ *   <li>Wraps inner ItemListing.getOffer in try/catch — a misbehaved
- *     21.1.230+, we're on 228) or need hand-written JSON for every
+ *       modded listing can't take down the whole profession.</li>
- *     trade. Reusing the event we already need for HUD pushes is
+ *   <li>Null offer returned from inner is propagated cleanly.</li>
- *     simpler and avoids touching the live NeoForge install.
+ *   <li>Null cost-A (theoretically possible from a reflection-built modded
+ *       MerchantOffer) is treated as "leave alone".</li>
+ * </ul>
  */
 @EventBusSubscriber(modid = BnsToolkit.MOD_ID)
 public final class VillagerTradeRebalance {
@@ -80,9 +85,18 @@ public final class VillagerTradeRebalance {
     private record SpurTradeWrapper(VillagerTrades.ItemListing inner) implements VillagerTrades.ItemListing {
         @Override
         public MerchantOffer getOffer(net.minecraft.world.entity.Entity entity, net.minecraft.util.RandomSource rand) {
-            MerchantOffer base = inner.getOffer(entity, rand);
+            final MerchantOffer base;
+            try {
+                base = inner.getOffer(entity, rand);
+            } catch (Throwable t) {
+                BnsToolkit.LOG.warn("[bns/trades] inner ItemListing {} threw {} — skipping offer",
+                        inner.getClass().getName(), t.toString());
+                return null;
+            }
             if (base == null) return null;
+
             ItemCost costA = base.getItemCostA();
+            if (costA == null) return base;  // can't swap; leave alone
             Optional<ItemCost> costB = base.getItemCostB();
             ItemStack result = base.getResult();
 
@@ -104,7 +118,7 @@ public final class VillagerTradeRebalance {
         int count = peek.getCount();
         CoinSwap swap = pickDenom(count);
         Item coinItem = BuiltInRegistries.ITEM.get(swap.itemId);
-        if (coinItem == Items.AIR) return cost;  // mod missing — leave vanilla cost
+        if (coinItem == Items.AIR) return cost;  // Numismatics not loaded
         return new ItemCost(coinItem, swap.count);
     }
 
@@ -122,8 +136,11 @@ public final class VillagerTradeRebalance {
     private record CoinSwap(ResourceLocation itemId, int count) {}
 
     private static CoinSwap pickDenom(int emeralds) {
-        if (emeralds >= 64) return new CoinSwap(COG_ID, Math.max(1, emeralds / 64));
+        // Round-to-nearest so 11 emeralds → 1 bevel (8) not 1 (and lose 3 value),
-        if (emeralds >= 8)  return new CoinSwap(BEVEL_ID, Math.max(1, emeralds / 8));
+        // 12 emeralds → 2 bevels (16). Trade-off: slight overpay at the boundary,
+        // but no silent floor haircut. Cap at 1 minimum so cost is never 0.
+        if (emeralds >= 64) return new CoinSwap(COG_ID, Math.max(1, (emeralds + 32) / 64));
+        if (emeralds >= 8)  return new CoinSwap(BEVEL_ID, Math.max(1, (emeralds + 4) / 8));
         return new CoinSwap(SPUR_ID, Math.max(1, emeralds));
     }
 }

src/main/java/uk/sijbers/bnstoolkit/network/BnsNetwork.java

@@ -7,6 +7,7 @@ import uk.sijbers.bnstoolkit.BnsToolkit;
 import uk.sijbers.bnstoolkit.network.c2s.RequestEconomySnapshotPacket;
 import uk.sijbers.bnstoolkit.network.c2s.RunBnsCommandPacket;
 import uk.sijbers.bnstoolkit.network.s2c.BountySnapshotPacket;
+import uk.sijbers.bnstoolkit.network.s2c.OpenScreenPacket;
 import uk.sijbers.bnstoolkit.network.s2c.PlotSnapshotPacket;
 import uk.sijbers.bnstoolkit.network.s2c.SellSnapshotPacket;
 import uk.sijbers.bnstoolkit.network.s2c.TierStateUpdatePacket;
@@ -31,7 +32,7 @@ import uk.sijbers.bnstoolkit.network.s2c.TierStateUpdatePacket;
 public final class BnsNetwork {
     private BnsNetwork() {}
 
-    public static final String VERSION = "0.2";
+    public static final String VERSION = "0.4";
 
     public static void register(IEventBus modBus) {
         modBus.addListener(BnsNetwork::onRegisterPayloads);
@@ -65,6 +66,10 @@ public final class BnsNetwork {
                 PlotSnapshotPacket.TYPE,
                 PlotSnapshotPacket.STREAM_CODEC,
                 PlotSnapshotPacket::handle);
+        reg.playToClient(
+                OpenScreenPacket.TYPE,
+                OpenScreenPacket.STREAM_CODEC,
+                OpenScreenPacket::handle);
 
         BnsToolkit.LOG.info("[bnstoolkit/net] registered payloads v{}", VERSION);
     }

src/main/java/uk/sijbers/bnstoolkit/network/ServerEconomyBridge.java

@@ -2,98 +2,210 @@ package uk.sijbers.bnstoolkit.network;
 
 import net.minecraft.commands.CommandSourceStack;
 import net.minecraft.nbt.CompoundTag;
-import net.minecraft.nbt.ListTag;
+import net.minecraft.resources.ResourceLocation;
-import net.minecraft.nbt.Tag;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.entity.player.Player;
 import net.neoforged.neoforge.network.PacketDistributor;
 import uk.sijbers.bnstoolkit.BnsToolkit;
-import uk.sijbers.bnstoolkit.data.Bounty;
 import uk.sijbers.bnstoolkit.data.CivicTier;
 import uk.sijbers.bnstoolkit.data.Plot;
 import uk.sijbers.bnstoolkit.data.SpurBalance;
 import uk.sijbers.bnstoolkit.network.s2c.BountySnapshotPacket;
+import uk.sijbers.bnstoolkit.network.s2c.OpenScreenPacket;
 import uk.sijbers.bnstoolkit.network.s2c.PlotSnapshotPacket;
 import uk.sijbers.bnstoolkit.network.s2c.SellSnapshotPacket;
 import uk.sijbers.bnstoolkit.network.s2c.TierStateUpdatePacket;
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Pattern;
 
 /**
- * Server-side bridge between the bnstoolkit network packets and the
+ * Server-side bridge between bnstoolkit packets and the KubeJS-owned
- * KubeJS-owned economy state.
+ * economy state.
  *
- * Reads: pull straight from player.persistentData (the NBT KubeJS writes).
+ * Reads pull straight from player NBT (and the KubeJS-attached server
- * Writes: route through the existing /bns chat commands via the server's
+ * NBT for plot ownership). Writes route through the existing /bns chat
- *   command stack — KubeJS is registered as a command-source handler,
+ * verbs via the server's command stack so KubeJS remains the source of
- *   so this delegates business logic instead of re-implementing it.
+ * truth for economy logic.
  *
- * The verb whitelist below is what lets the screens trigger the SAME
+ * <h2>Hardening</h2>
- * verbs the player can type — and nothing else.
+ * <ul>
+ *   <li>Per-player token-bucket rate limit (10 commands/sec, burst 20)</li>
+ *   <li>Structured verb whitelist — args are parsed into (verb,
+ *       params) and each param validated against an explicit type, then
+ *       the command string is rebuilt from a trusted template. No
+ *       prefix-startsWith match.</li>
+ *   <li>Identifier inputs (item ids, bounty ids, plot ids, screen names)
+ *       are bounded length + regex-validated.</li>
+ *   <li>Sanitises args before logging (no log-injection).</li>
+ *   <li>Per-player in-flight guard on tier upgrades to close the
+ *       double-spend race window.</li>
+ * </ul>
  */
 public final class ServerEconomyBridge {
     private ServerEconomyBridge() {}
 
-    private static final Set<String> SAFE_VERBS = Set.of(
+    // ─── Validation patterns ─────────────────────────────────────────
-            "tier upgrade",
+    // Match Minecraft ResourceLocation: namespace + path. Allow_kebab.
-            "sell ",       // followed by item id + count
+    private static final Pattern ITEM_ID = Pattern.compile("^[a-z0-9_\\-.]+:[a-z0-9_/\\-.]+$");
-            "bounty accept ",
+    private static final Pattern BOUNTY_ID = Pattern.compile("^[a-z0-9_]{1,32}$");
-            "bounty cancel ",
+    private static final Pattern PLOT_ID = Pattern.compile("^[a-z0-9_]{1,16}$");
-            "bounty turnin ",
+    private static final Pattern SCREEN_NAME = Pattern.compile("^[a-z]{2,12}$");
-            "plot buy ",
+    private static final int MAX_COUNT = 64 * 36;  // can't exceed inventory anyway
-            "plot release "
+
-    );
+    // ─── Rate limiting ───────────────────────────────────────────────
+    // Per-player token bucket: 10 tokens, refill 10/sec. Burst 20 (mass-sell)
+    // is fine; sustained spam past 10/sec drops silently.
+    private static final int RATE_CAPACITY = 20;
+    private static final int RATE_REFILL_PER_SEC = 10;
+    private static final Map<UUID, RateBucket> BUCKETS = new ConcurrentHashMap<>();
+    private static final Map<UUID, Long> IN_FLIGHT_TIER = new ConcurrentHashMap<>();
+
+    private static boolean takeToken(UUID id) {
+        long now = System.currentTimeMillis();
+        RateBucket b = BUCKETS.computeIfAbsent(id, k -> new RateBucket(RATE_CAPACITY, now));
+        synchronized (b) {
+            long elapsed = now - b.lastRefillMs;
+            if (elapsed > 0) {
+                double add = elapsed * RATE_REFILL_PER_SEC / 1000.0;
+                b.tokens = Math.min(RATE_CAPACITY, b.tokens + add);
+                b.lastRefillMs = now;
+            }
+            if (b.tokens >= 1.0) {
+                b.tokens -= 1.0;
+                return true;
+            }
+            return false;
+        }
+    }
+
+    private static final class RateBucket {
+        double tokens;
+        long lastRefillMs;
+        RateBucket(int initial, long now) { this.tokens = initial; this.lastRefillMs = now; }
+    }
 
     // ─── Routed commands ─────────────────────────────────────────────
 
+    /** Validates + parses + executes a player-initiated /bns verb. */
     public static void runWhitelisted(Player player, String args) {
         if (!(player instanceof ServerPlayer sp)) return;
-        if (args == null || args.isEmpty()) return;
+        if (args == null || args.length() > 80) return;  // hard cap
 
-        boolean ok = false;
+        if (!takeToken(sp.getUUID())) {
-        for (String prefix : SAFE_VERBS) {
+            BnsToolkit.LOG.debug("[bns/bridge] rate-limited {}", sp.getName().getString());
-            if (args.equals(prefix.trim()) || args.startsWith(prefix)) { ok = true; break; }
+            return;
         }
-        if (!ok) {
+
-            BnsToolkit.LOG.warn("[bns/bridge] rejected non-whitelisted verb from {}: {}", sp.getName().getString(), args);
+        // Parse `args` into tokens (whitespace-separated). All idents
+        // already constrained to safe charsets by the regexes below.
+        String[] parts = args.trim().split("\\s+");
+        if (parts.length == 0) return;
+
+        String safe = null;
+        switch (parts[0]) {
+            case "tier":
+                if (parts.length == 2 && "upgrade".equals(parts[1])) {
+                    safe = handleTierUpgrade(sp);
+                }
+                break;
+            case "sell":
+                if (parts.length == 3 && ITEM_ID.matcher(parts[1]).matches()) {
+                    int n = parsePositiveInt(parts[2]);
+                    if (n > 0 && n <= MAX_COUNT) safe = "sell " + parts[1] + " " + n;
+                }
+                break;
+            case "bounty":
+                if (parts.length == 3
+                        && ("accept".equals(parts[1]) || "cancel".equals(parts[1]) || "turnin".equals(parts[1]))
+                        && BOUNTY_ID.matcher(parts[2]).matches()) {
+                    safe = "bounty " + parts[1] + " " + parts[2];
+                }
+                break;
+            case "plot":
+                if (parts.length == 3
+                        && ("buy".equals(parts[1]) || "release".equals(parts[1]))
+                        && PLOT_ID.matcher(parts[2]).matches()) {
+                    safe = "plot " + parts[1] + " " + parts[2];
+                }
+                break;
+        }
+
+        if (safe == null) {
+            BnsToolkit.LOG.warn("[bns/bridge] rejected verb from {}: {}",
+                    sp.getName().getString(), sanitize(args));
             return;
         }
 
         CommandSourceStack src = sp.createCommandSourceStack();
-        String full = "bns " + args;
+        String full = "bns " + safe;
         BnsToolkit.LOG.info("[bns/bridge] {} runs '{}'", sp.getName().getString(), full);
         sp.server.getCommands().performPrefixedCommand(src, full);
 
-        // After any state-mutating verb, push a fresh snapshot relevant to it.
+        // Post-mutation snapshot push, matched to the verb.
-        if (args.startsWith("tier")) {
+        if (safe.startsWith("tier")) {
             pushTierUpdate(sp);
-        } else if (args.startsWith("sell")) {
+        } else if (safe.startsWith("sell")) {
             pushTierUpdate(sp);
             pushSellSnapshot(sp);
-        } else if (args.startsWith("bounty")) {
+        } else if (safe.startsWith("bounty")) {
             pushTierUpdate(sp);
             pushBountySnapshot(sp);
-        } else if (args.startsWith("plot")) {
+        } else if (safe.startsWith("plot")) {
             pushTierUpdate(sp);
             pushPlotSnapshot(sp);
         }
     }
 
+    /**
+     * Tier upgrade guard. KubeJS checks balance then debits — a spammy
+     * client could race two requests through. Single-player-flight here
+     * forces one upgrade-attempt at a time; the second arrives, sees
+     * the guard, and is dropped.
+     */
+    private static String handleTierUpgrade(ServerPlayer sp) {
+        long now = System.currentTimeMillis();
+        Long last = IN_FLIGHT_TIER.get(sp.getUUID());
+        if (last != null && now - last < 500) return null;
+        IN_FLIGHT_TIER.put(sp.getUUID(), now);
+        return "tier upgrade";
+    }
+
+    private static int parsePositiveInt(String s) {
+        if (s.length() > 5) return -1;  // 99999 max
+        try {
+            int n = Integer.parseInt(s);
+            return n > 0 ? n : -1;
+        } catch (NumberFormatException e) {
+            return -1;
+        }
+    }
+
+    private static String sanitize(String s) {
+        if (s == null) return "<null>";
+        if (s.length() > 64) s = s.substring(0, 64) + "...";
+        return s.replaceAll("[\\p{Cntrl}]", "?");
+    }
+
     // ─── Snapshot pushes ─────────────────────────────────────────────
 
     public static void pushSnapshot(Player player, String kind) {
         if (!(player instanceof ServerPlayer sp)) return;
+        if (!takeToken(sp.getUUID())) return;
         switch (kind) {
             case "TIER"   -> pushTierUpdate(sp);
             case "SELL"   -> { pushTierUpdate(sp); pushSellSnapshot(sp); }
             case "BOUNTY" -> { pushTierUpdate(sp); pushBountySnapshot(sp); }
             case "PLOT"   -> { pushTierUpdate(sp); pushPlotSnapshot(sp); }
-            default       -> { pushTierUpdate(sp); pushSellSnapshot(sp); pushBountySnapshot(sp); pushPlotSnapshot(sp); }
+            case "ALL"    -> { pushTierUpdate(sp); pushSellSnapshot(sp); pushBountySnapshot(sp); pushPlotSnapshot(sp); }
+            default       -> BnsToolkit.LOG.debug("[bns/bridge] unknown snapshot kind {}", sanitize(kind));
         }
     }
 
@@ -121,33 +233,38 @@ public final class ServerEconomyBridge {
 
     public static void pushBountySnapshot(ServerPlayer sp) {
         CompoundTag data = sp.getPersistentData();
-        List<String> poolIds = new ArrayList<>();
-        Map<String, BountySnapshotPacket.ActiveEntry> active = new HashMap<>();
-        List<String> completed = new ArrayList<>();
 
-        if (data.contains("bnsBounties")) {
+        // Daily pool: keys of bnsBountyPool compound.
-            CompoundTag bnt = data.getCompound("bnsBounties");
+        List<String> poolIds = new ArrayList<>();
-            if (bnt.contains("pool")) {
+        if (data.contains("bnsBountyPool")) {
-                ListTag pool = bnt.getList("pool", Tag.TAG_STRING);
+            CompoundTag pool = data.getCompound("bnsBountyPool");
-                for (int i = 0; i < pool.size(); i++) poolIds.add(pool.getString(i));
+            for (String key : pool.getAllKeys()) poolIds.add(key);
         }
-            if (bnt.contains("active")) {
+
-                CompoundTag act = bnt.getCompound("active");
+        // Active set: bnsBountyActive compound of id -> {progress, target, reward, ...}
+        Map<String, BountySnapshotPacket.ActiveEntry> active = new HashMap<>();
+        if (data.contains("bnsBountyActive")) {
+            CompoundTag act = data.getCompound("bnsBountyActive");
             for (String id : act.getAllKeys()) {
                 CompoundTag e = act.getCompound(id);
-                    int progress = e.getInt("progress");
+                active.put(id, new BountySnapshotPacket.ActiveEntry(
-                    int target = e.getInt("target");
+                        e.getInt("progress"),
-                    long reward = e.getInt("reward");
+                        e.getInt("target"),
-                    active.put(id, new BountySnapshotPacket.ActiveEntry(progress, target, reward));
+                        e.getInt("reward")));
-                }
+            }
-            }
+        }
-            if (bnt.contains("completed")) {
+
-                CompoundTag cmp = bnt.getCompound("completed");
+        // Completed (cooldown) set: bnsBountyCompleted compound of id -> long cooldown-end ms.
-                for (String id : cmp.getAllKeys()) completed.add(id);
+        // Only include entries still on cooldown (cooldown-end > now).
+        List<String> completed = new ArrayList<>();
+        long now = System.currentTimeMillis();
+        if (data.contains("bnsBountyCompleted")) {
+            CompoundTag cmp = data.getCompound("bnsBountyCompleted");
+            for (String id : cmp.getAllKeys()) {
+                if (cmp.getLong(id) > now) completed.add(id);
             }
         }
 
-        // Slot cap from tier
         int tier = data.contains("bnsTier") ? data.getInt("bnsTier") : 1;
         if (tier < 1 || tier > CivicTier.MAX) tier = 1;
         int slotCap = CivicTier.byId(tier).dailyBountySlots();
@@ -156,46 +273,77 @@ public final class ServerEconomyBridge {
     }
 
     public static void pushPlotSnapshot(ServerPlayer sp) {
-        // Plot ownership is tracked in level.persistentData (world scope), not per-player.
-        // Read it via the world's saved data CompoundTag the KubeJS code writes to.
         Map<String, String> owners = new HashMap<>();
+        List<String> ownedIds = new ArrayList<>();
         for (Plot p : Plot.ALL) owners.put(p.id(), "");
 
-        net.minecraft.server.level.ServerLevel level = sp.serverLevel();
+        // KubeJS attaches its server-scope persistentData to MinecraftServer via
-        // KubeJS Persistent Data (world scope) lives at level.getDataStorage with key 'kubejs'
+        // a mixin (kjs$getPersistentData). Reflective access avoids a hard
-        // but to avoid coupling, read from the per-player bnsOwnedPlots NBT array we set
+        // compileOnly dep on KubeJS; if the method is missing, fall back to
-        // alongside ownership in plots.js. Fall back to empty.
+        // empty (the screen shows "all free" which is the correct degraded view).
-        List<String> ownedIds = new ArrayList<>();
+        CompoundTag serverData = getKubeJSServerData(sp.server);
-        CompoundTag pdata = sp.getPersistentData();
+        if (serverData.contains("bnsPlots")) {
-        if (pdata.contains("bnsOwnedPlots")) {
+            CompoundTag map = serverData.getCompound("bnsPlots");
-            ListTag list = pdata.getList("bnsOwnedPlots", Tag.TAG_STRING);
+            String myUuid = sp.getUUID().toString();
-            for (int i = 0; i < list.size(); i++) {
+            for (String plotId : map.getAllKeys()) {
-                String id = list.getString(i);
+                String uuidStr = map.getString(plotId);
-                ownedIds.add(id);
+                if (uuidStr.equals(myUuid)) {
-                owners.put(id, sp.getName().getString());
+                    ownedIds.add(plotId);
+                    owners.put(plotId, sp.getName().getString());
+                } else {
+                    owners.put(plotId, resolveOwnerName(sp.server, uuidStr));
                 }
             }
-        // Mark plots owned by other players as taken — read everybody's
-        // persistentData via the level's player list.
-        for (ServerPlayer other : sp.server.getPlayerList().getPlayers()) {
-            if (other == sp) continue;
-            CompoundTag od = other.getPersistentData();
-            if (!od.contains("bnsOwnedPlots")) continue;
-            ListTag list = od.getList("bnsOwnedPlots", Tag.TAG_STRING);
-            for (int i = 0; i < list.size(); i++) {
-                String id = list.getString(i);
-                if (!ownedIds.contains(id)) owners.put(id, other.getName().getString());
-            }
         }
 
-        int tier = pdata.contains("bnsTier") ? pdata.getInt("bnsTier") : 1;
+        int tier = sp.getPersistentData().contains("bnsTier") ? sp.getPersistentData().getInt("bnsTier") : 1;
         if (tier < 1 || tier > CivicTier.MAX) tier = 1;
         int slotCap = CivicTier.byId(tier).plotSlots();
 
         PacketDistributor.sendToPlayer(sp, new PlotSnapshotPacket(owners, slotCap, ownedIds));
     }
 
-    // Defensive: bounties pool format uses the same shape we know about
+    /** Opens a bnstoolkit screen on the calling player (used by /bns open). */
-    @SuppressWarnings("unused")
+    public static void openScreen(ServerPlayer sp, String which) {
-    private static Bounty resolveBounty(String id) { return Bounty.byId(id); }
+        if (!SCREEN_NAME.matcher(which).matches()) return;
+        PacketDistributor.sendToPlayer(sp, new OpenScreenPacket(which));
+    }
+
+    // ─── KubeJS server-data accessor ─────────────────────────────────
+
+    private static volatile Method kjsServerPersistentData;
+    private static volatile boolean kjsLookupAttempted;
+
+    private static CompoundTag getKubeJSServerData(MinecraftServer server) {
+        if (kjsServerPersistentData == null && !kjsLookupAttempted) {
+            kjsLookupAttempted = true;
+            try {
+                kjsServerPersistentData = server.getClass().getMethod("kjs$getPersistentData");
+                BnsToolkit.LOG.info("[bns/bridge] linked KubeJS server-scope persistentData via mixin");
+            } catch (NoSuchMethodException e) {
+                BnsToolkit.LOG.warn("[bns/bridge] KubeJS kjs$getPersistentData not found — plot snapshot will be empty");
+            }
+        }
+        if (kjsServerPersistentData == null) return new CompoundTag();
+        try {
+            return (CompoundTag) kjsServerPersistentData.invoke(server);
+        } catch (Throwable t) {
+            BnsToolkit.LOG.error("[bns/bridge] failed to read KubeJS server data: {}", t.toString());
+            return new CompoundTag();
+        }
+    }
+
+    private static String resolveOwnerName(MinecraftServer server, String uuidStr) {
+        try {
+            UUID id = UUID.fromString(uuidStr);
+            ServerPlayer online = server.getPlayerList().getPlayer(id);
+            if (online != null) return online.getName().getString();
+            // Offline: try the game-profile cache for the cached display name.
+            return server.getProfileCache().get(id)
+                    .map(profile -> profile.getName())
+                    .orElse("uuid:" + uuidStr.substring(0, 8));
+        } catch (Exception e) {
+            return "?";
+        }
+    }
 }

src/main/java/uk/sijbers/bnstoolkit/network/c2s/RequestEconomySnapshotPacket.java

@@ -28,7 +28,7 @@ public record RequestEconomySnapshotPacket(String kind) implements CustomPacketP
 
     public static final StreamCodec<RegistryFriendlyByteBuf, RequestEconomySnapshotPacket> STREAM_CODEC =
             StreamCodec.composite(
-                    ByteBufCodecs.STRING_UTF8, RequestEconomySnapshotPacket::kind,
+                    ByteBufCodecs.stringUtf8(8), RequestEconomySnapshotPacket::kind,
                     RequestEconomySnapshotPacket::new);
 
     @Override

src/main/java/uk/sijbers/bnstoolkit/network/c2s/RunBnsCommandPacket.java

@@ -33,7 +33,7 @@ public record RunBnsCommandPacket(String args) implements CustomPacketPayload {
 
     public static final StreamCodec<RegistryFriendlyByteBuf, RunBnsCommandPacket> STREAM_CODEC =
             StreamCodec.composite(
-                    ByteBufCodecs.STRING_UTF8, RunBnsCommandPacket::args,
+                    ByteBufCodecs.stringUtf8(80), RunBnsCommandPacket::args,
                     RunBnsCommandPacket::new);
 
     @Override

src/main/java/uk/sijbers/bnstoolkit/network/s2c/BountySnapshotPacket.java

@@ -61,6 +61,8 @@ public record BountySnapshotPacket(
             }
             ClientBnsState.completedIds.clear();
             ClientBnsState.completedIds.addAll(pkt.completedIds);
+            // pkt.completedIds is List by wire format; the client cache is a Set
+            // so per-frame state lookups in BountyBoardScreen are O(1).
             ClientBnsState.bountySlotCap = pkt.slotCap;
         });
     }

src/main/java/uk/sijbers/bnstoolkit/network/s2c/OpenScreenPacket.java

@@ -0,0 +1,42 @@
+package uk.sijbers.bnstoolkit.network.s2c;
+
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceLocation;
+import net.neoforged.neoforge.network.handling.IPayloadContext;
+import uk.sijbers.bnstoolkit.BnsToolkit;
+import uk.sijbers.bnstoolkit.client.OpenScreenDispatcher;
+
+/**
+ * S2C: open a bnstoolkit screen on the receiving client.
+ *
+ * Server triggers this in response to {@code /bns open <screen>} (which
+ * NPC dialogue, FTB Quests reward commands, command blocks, etc. can
+ * invoke). The `which` field selects the screen — see
+ * {@link OpenScreenDispatcher} for the screen ↔ name mapping.
+ *
+ * Decode-side class loading note: this packet must NOT import any
+ * client-only types directly. Dispatching lives in
+ * {@link OpenScreenDispatcher}, which itself avoids loading screen
+ * classes until its dispatch method runs (client-side only).
+ */
+public record OpenScreenPacket(String which) implements CustomPacketPayload {
+    public static final Type<OpenScreenPacket> TYPE = new Type<>(
+            ResourceLocation.fromNamespaceAndPath(BnsToolkit.MOD_ID, "open_screen"));
+
+    public static final StreamCodec<RegistryFriendlyByteBuf, OpenScreenPacket> STREAM_CODEC =
+            StreamCodec.composite(
+                    ByteBufCodecs.stringUtf8(16), OpenScreenPacket::which,
+                    OpenScreenPacket::new);
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+
+    public static void handle(OpenScreenPacket pkt, IPayloadContext ctx) {
+        ctx.enqueueWork(() -> OpenScreenDispatcher.open(pkt.which));
+    }
+}

src/main/java/uk/sijbers/bnstoolkit/server/BnsServerCommands.java

@@ -0,0 +1,83 @@
+package uk.sijbers.bnstoolkit.server;
+
+import com.mojang.brigadier.arguments.StringArgumentType;
+import com.mojang.brigadier.builder.LiteralArgumentBuilder;
+import com.mojang.brigadier.suggestion.Suggestions;
+import com.mojang.brigadier.suggestion.SuggestionsBuilder;
+import net.minecraft.commands.CommandSourceStack;
+import net.minecraft.commands.Commands;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.neoforged.bus.api.SubscribeEvent;
+import net.neoforged.fml.common.EventBusSubscriber;
+import net.neoforged.neoforge.event.RegisterCommandsEvent;
+import uk.sijbers.bnstoolkit.BnsToolkit;
+import uk.sijbers.bnstoolkit.network.ServerEconomyBridge;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Bnstoolkit-side /bns subcommands. Brigadier merges this with the
+ * KubeJS-registered /bns tree so both sets of children appear under the
+ * same root.
+ *
+ * Subcommands provided here:
+ *   /bns open <screen>   — push an OpenScreenPacket to the calling player.
+ *                          {@code screen} ∈ {hub, tier, bounty, plot, shop, questlog}.
+ *
+ * This is the entry point Easy NPC dialogue, FTB Quests reward commands,
+ * command blocks, and /trigger objectives use to route to a bnstoolkit
+ * screen. Player-context-only — running from console / a command block
+ * with a fake source just returns 0 (no harm done).
+ */
+@EventBusSubscriber(modid = BnsToolkit.MOD_ID)
+public final class BnsServerCommands {
+    private BnsServerCommands() {}
+
+    private static final String[] SCREEN_NAMES = {
+            "hub", "tier", "bounty", "plot", "shop", "questlog"
+    };
+
+    @SubscribeEvent
+    public static void onRegisterCommands(RegisterCommandsEvent event) {
+        LiteralArgumentBuilder<CommandSourceStack> bns = Commands.literal("bns")
+                .then(Commands.literal("open")
+                        .then(Commands.argument("screen", StringArgumentType.word())
+                                .suggests(BnsServerCommands::suggestScreens)
+                                .executes(ctx -> {
+                                    String which = StringArgumentType.getString(ctx, "screen");
+                                    return openForPlayer(ctx.getSource(), which);
+                                })));
+        event.getDispatcher().register(bns);
+        BnsToolkit.LOG.info("[bnstoolkit] registered /bns open <screen> command");
+    }
+
+    private static CompletableFuture<Suggestions> suggestScreens(
+            com.mojang.brigadier.context.CommandContext<CommandSourceStack> ctx,
+            SuggestionsBuilder builder) {
+        String prefix = builder.getRemaining().toLowerCase();
+        for (String s : SCREEN_NAMES) {
+            if (s.startsWith(prefix)) builder.suggest(s);
+        }
+        return builder.buildFuture();
+    }
+
+    private static int openForPlayer(CommandSourceStack src, String which) {
+        ServerPlayer sp = src.getPlayer();
+        if (sp == null) {
+            src.sendFailure(Component.literal("/bns open must be run as a player"));
+            return 0;
+        }
+        // Validate before dispatch — server-side check belt + suspenders with
+        // the screen-name regex in ServerEconomyBridge.openScreen.
+        boolean ok = false;
+        for (String s : SCREEN_NAMES) if (s.equals(which)) { ok = true; break; }
+        if (!ok) {
+            src.sendFailure(Component.literal("Unknown screen: " + which
+                    + ". Options: hub, tier, bounty, plot, shop, questlog"));
+            return 0;
+        }
+        ServerEconomyBridge.openScreen(sp, which);
+        return 1;
+    }
+}

src/main/resources/assets/bnstoolkit/lang/en_us.json

@@ -1,11 +1,13 @@
 {
   "key.category.bnstoolkit": "Brass and Sigil",
-  "key.bnstoolkit.tier": "Open Tier Ladder",
+  "key.bnstoolkit.hub": "Open Brass and Sigil Hub",
-  "key.bnstoolkit.bounties": "Open Bounty Board",
+  "key.bnstoolkit.tier": "Open Tier Ladder (direct)",
-  "key.bnstoolkit.plots": "Open Plot Office",
+  "key.bnstoolkit.bounties": "Open Bounty Board (direct)",
-  "key.bnstoolkit.shop": "Open Bazaar Shop",
+  "key.bnstoolkit.plots": "Open Plot Office (direct)",
-  "key.bnstoolkit.questlog": "Open Quest Log",
+  "key.bnstoolkit.shop": "Open Bazaar Shop (direct)",
+  "key.bnstoolkit.questlog": "Open Quest Log (direct)",
 
+  "screen.bnstoolkit.hub": "Brass and Sigil",
   "screen.bnstoolkit.tier_upgrade": "Civic Tier",
   "screen.bnstoolkit.bounty_board": "Bounty Board",
   "screen.bnstoolkit.quest_log": "Quest Log",